Engineers at the California Institute of Technology (Caltech) have developed tiny, inexpensive silicon microchips that can be incorporated into handheld devices, such as smartphones, and used to identify explosives and other dangerous objects.
According to Ali Hajimiri, the Thomas G. Myers professor of electrical engineering at Caltech, the microchips generate and radiate high-frequency electromagnetic waves that can penetrate a range of different materials without the ionizing damage caused by x-rays. The chip is capable of emitting signals more than 1,000 times stronger than existing approaches in any specified direction.
With assistance from IBM, the team overcame several hurdles to create the fingertip-sized silicon chips that operate at terahertz frequencies. Though terahertz imaging and scanning is not a new technology, most existing systems require large and expensive laser setups that often need to operate within a specific temperature range.
“Using the same low-cost, integrated-circuit technology that’s used to make the microchips found in our cell phones and notepads today, we have made a silicon chip that can operate at nearly 300 times their speed,” Hajimiri said. “These chips will enable a new generation of extremely versatile sensors.”
Hajimiri and his team also faced another problem with their choice of materials. Silicon chips are not traditionally designed to operate at teraherz frequencies; however, the team was able to work around the issue by harnessing the collective strength of multiple transistors operating simultaneously. The engineering team was also able to transmit the terahertz signal by incorporating small metal segments capable of simultaneous signal radiation onto the silicon chip.
